Telephone system



A. B. PREUSS TELEPHONE SYSTEM Aug. 1, 1933.

Filed Oct. 7 1951 2 Sheets-Sheet l PM? Fflsxander Bruno Prsuss J? I. N3

on o o ooooaoen 0 o 0 0 0 0 0 0 0 o occo 0 oz o u n o a A. B. PREUSS TELEPHONE SYSTEM 7 Aug. 1, 1933.

Filed Oct. 7, 1951 '2 Sheets-Sheet 2 rm Hlexandez- Brut-u: Freuss Patented Aug. 1, 1933 7 1,920,214 TELEPHONE SYSTEM Alexander Bruno Preuss, Berlin-Charlottenburg,

Germany,

assignor to Siemens &

liiaiske Aktiengesellschaft, Siemensstadt near Berlin,

Germany Application (lotober 7, 1931, Serial'No. 567,481, and'in Germany October 10, 1930 11 Claims. (Cl. 179l.8

In order not to increase the number of selecting stages to be used for a connection in telephone systems with a plurality of exchanges above the numberof stages necessitated by the number of connecting lines and also in order toavoid difierently placed subscribers numbers well as to facilitate the setting up of connections by keeping the number of stations associated with the connecting line numbers as low as possible, it has been suggested to seize a plurality of lines outgoing in various directions or to let the calling station simultaneously set a plurality of switches in various exchanges. These arrangements which are of special advantage for certain circuits are in other cases encumbered by disadvantages which cannot be discounted either in technical or economical regards.

In order to avoid a simultaneous seizure of lines extending in different traflic directions it has been suggested to arrange-by the arrangement of a special impulse sender at the subscribers station-that the seizure of a connecting route outgoin in a certain traffic direction is initiated in dependence upon the impulse series, which arrangement necessitates complications at the impulse sender associated with the subscribers station.

The object of the invention is to bring about an arrangement by means of which, asfar as possible, all disadvantages accompanying known arrangements as well as an increase of selecting stages above the number necessitated by the number of subscribers stations have been eliminated in a' simple manner. The quantity of special auxiliary devicesneccssary to satisfy all technical and operative demands are further brought to a minimum. The invention solves the problem by arranging that a numerical impulse receiver over which connections of certain trafiic directions are set up is set by means of a switch over which connections of other traffic direction extend.

Embodiments of the invention are shown in the drawings to which embodiments the invention, however, is not limited. Fig. 1 is a trunk ing diagram showing the general'layout of a telephone system embodying the invention; Fig. 2 is a circuit diagram showing more in detail the essential features of Fig. 1; while Fig. 3 is a circuit diagram showing a modification of the systern shown in Fig. 2.

Referring now to Fig. 1, Tn represents a subscribers station which has access to a group selector IGW over the preselector IVW. At the first number impulse which is sent out for the setting of the group selector IGW an impulse for the switch MW which seizes a free group selector IGWZ; associated -with another exchange is effected over the line (1.72

If the connection is to GO be set up internally, for example to the .sub scriber Tnl, the group selector IGW is set to a free line within the level I, 5, 6,- group selector IIGWa is seized 0. The second whereupon the connection is extended over the final selector LW to the subscriber Tnl- If a subscriber associated with another-exchange, for example the subscriber T112, is to be called, the group selector IGW is set to "one of the 1eve1s'2, 3, l, 7,8 or '9. When the group selector IGW is raised to these levels it sends out impulses for the setting of the IGV/b with the result that the the group selector IIGW.

group selector succeeding im- It should be noted that in the case of internal connections the switch MW is released at the hunting of the group selector IGW for a freeline in the levels 1,5, 6, 0.

In conjunction with Fig. 2 the connection will be described in setting up of a '80 which case it should be noted that the switch wiper die of the group selector IGW together with the associated contact bank shown in Fig. 2 only refers to the shown embodiment to the extent of taking over 35 the functions of the contacts multiply connected to'earth in the, contact banks of the switch wiper bgw inwhich case the line Ll can be omitted. The operation of the switch wiper clk will be described in detail in a suitable paragraph. 1 When the subscriber at a subscribers station Tn lifts his receiver, the preselector IVW is set to a free line, forexample, the lines Lal, Lbl, Lcl,

in any known manner. Relays energized whereupon the following test circuit is up over line Lci: earth,

A and B are vwinding II of relays B and A, off-normal contact 14k of the group selector IGW, contacts 131), 1b, wiper cvw of the preselector I'VW, not shown switching devices in line Lc. By the energization of relay B the contact lb is thrownoverwhereby the seizing relay C is energized. This relay actuates its contacts 50, 60, 7c, 80, and 190.

By the energization of relay A contacts 251,3(1, and 4a are thrown over. By the throwing over of contact72a, a

test relay P of the group select-or over contact 60, and by the th IGW is earthed rowing over of contacts 30. and 4a the following circuitis established: earth-contacts 29:0, 1570, winding III of relay V, contacts 4a, 7c, 3a, ro

tary off -normal energized in this circuit. The opening of contact 19c prevents the starting relay R from re energizing when contact 207) is closed. The rotary magnet D, when energized, actuatedcontact 17d whereby relay V is energized over its winding I. Relay V breaks the circuit for the rotary magnet at contact 11 whereupon contactv 17d returns to normal. The alternating. interaction between winding I of relay V and the rotary magnet D continues until the switch wipers agw, bow, cow, and dgw have leftthe contact bank. of

the switch whereupon these drop down due to their own weight and take up their normal position. The off-normal contacts are thrown over due to this movement and therotary off-normal contacts, for example 1620, are re-closed. After the opening of the off-normal contacts the group selector is restored to its normal position and thereby set in preparation for the setting up of a fresh connection.

It will now be assumed that the subscriber at a subscribers station Tn has not selected any of the digits '1, 5, 6 or Oin the first impulse series by which he can obtain a connection within the exchange. VStl, but as the first impulse. series selected the digit 4 whereby he reaches the exchange VStZ over the switch MW and the junction line La l, Lia LL04.

When the group selector is seized relays C, A, B, and.V are energized in the manner already described. At the transmission of the first impulse relay R is energized due to the operation of the off-normal contacts over the following circuit: earth, contact 20p, off-normal contact 15k, relay R, contact 190, battery, earth.

By the energization ofv relay R contacts 241': and 251 are thrown OVQIZ. By the throwing over of contact 251' the interrupter U will be connected tothe rotary magnet-Dmw of the switch MW, The wipers of the switch MW are advanced step-by-step. .When the switch wiper cmw encounters a tree line, for example the line Lee, the following. circuit is established; earth,

.battery, not shown switching devices, relay 02,

line Lc i, relay X, switch wiper cmw,.windings II and I of relay T, contact 241', earth, in which circuit relays T, X and C2'are energized. By the energization of relay T contacts 261?, 27f, 28t, and 2% are actuated. By the opening of contact 2% the circuit for rotary magnet D is broken. By contacts 271? and 28B the line Lax-3, L123 is switched through. Contact 2615 short-circuits winding I.

of relay T with the consequence that the seized line will be guarded in known manner. Relay X opens contact 303:. Assuming that the lines reached by the switch MW are free, the m-contacts of the other relay X, located in the lines associated with the switch MW, are closed which prevents relay G from releasing. Relay G maintains its contact 319 closed. The normal position'of this contact is indicated by dotted lines. It will thus be seen that as long as free lines can be reached by the switch MW. the relay G is maintained energized. Only when a busy signal" from all the outgoing lines is received relay G releases whereupon contact 319 takes up the normal position indicated by dotted lines, a switching operation, the purpose of which will be explained later. On the energization of relay C2 the contact 3202 among. others will be actuated whereby the group selector IGWb is ready to hunt.

pulse sent out over the line La3.

At the end of this impulse series during which the relay A has been maintained energized an extended period the relay V, operating as a slowacting relay, releases as already described. Contactllv is closed by this operation and the following circuit for the rotary magnet D is set up:

earth, contact 2629, ofi-normal contact l5k,.con-

tact 11v, rotary magnet D, battery, earth. Contact 16w is opened and contact 17d is closed. Relay V is hereby ire-energized over its Winding I which causes contact 111) to be re-opened. The rotary magnet releases and this interaction continues until the switch wiper cgw settles upon the fifth contact in the fourth level to which battery f magnet D) contact 22p, switch wiper agw of the group selector, first contact in the contact bank 4 or" the switch wiper agw, line L113, contact 2715,-

switch wiper amw oi the switch MW, line Laa, relay A1, battery, earth. Relay A1 will be energized by this impulse and is utilized for the setting of the first group selector IGWb in any known manner. Upon the energization of relay V at the first rotary step of the group selector IGW the circuit for the rotary magnet D is broken by contact 1122. Rotary magnet D releases whereupon contact 17d is restored to normal. Relay V is short-circuited over its winding I and thereby releases. At this release contact 1022 is opened and contact 1112 closed. This ends the first im- When the switch wipers agw-dgw are set to the second contact in the level 4 at the succeeding energization of the rotary magnet D, relay V also is caused to be re-energized over contact 17d. Contact 101) is closed whereby a second impulse reaches relay A1 over the line La3, L114}. When the switch wipers of the group selector reach the fifth contact of level i a test circuit is established which brings the switch to rest as already de scribed in a previous paragraph. This test circuit extends over: earth, battery, contact 3157,

fifth contact in level 4 of the contact bank of the rest in the manner already described. By the opening of contact 20p the circuit for relayR will be broken over the switch wiper dgw (which can be constructed as a multiple contact) if a looking circuit for relay R has not been set up. This extends over: earth, switch wiper dgugsegment 4. in the level 4 of the switch wiper dgw, resistance W13, winding of relay R, contact 190, battery, earth. The resistance W2'3 is so calculated that relay R is maintained energized whereas the rotary magnet D receives insufficient cur.- rent over contact 111) and resistance Wi3 to be energized. As contact 1012 was closed at each rotary step or" the switch an impulse is sent out at each closing of contact 1022 which reaches relay A1 of the groupselector IGWb over the multiplyconnected earth at the contacts in the contact banks of the switch wiper bgw over contact 102),

etc.

It is not absolutely necessary to have the contact banks of the group selector connected up in the manner shown in Fig. 2. Instead of thecon-v taots brushed by the switch wiper bgw to which earth is connected, a multiple contact dk can be provided the contactbanl: of which is diagram matically "shown in level 3. In such a case the line'Li can be omitted. Impulses can be generated by the opening and closing of contact 102) in the manner already described and. shown. In such a case the segment swept by the switch wiper dlc can be made of a continuous metal strip not split up into'individual contacts. The transmission of impulses will be limited by the energization of relay P, contact 22p among others being thrown over.

If the impulses are to be generated by the a'uxilbe effected by the segment, brushed by the switch contact contact.

wiper dis, being undivided in which case contact 101) can be dispensed with, theswitch wiper agw and-the contacts swept/by this wiper being so constructed that when the switch wiper apw sweeps the contact banks make and break intervals suitable to make up the impulse series can be obtained. I

It should be. noted that in such cases in which the switch wiper bow is not'necessary to the impulse series the contact banks brushed by this wiperneed not be connected in the manner shown in the drawings. In such a case the contacts over which connections must extend to the switch MW ca'n,.moreovcr, be combined in any known man It is also not necessary to restrict'the impulse seriesby the energization of the test relay. The

impulse seriesfor example, could be ended by utilizing the level contact die as an impulse generator, as the lever contactdlc possesses earthed contacts only in thefirst positions whereas the last positions are designed as a one-piece segment.

one-piece segment. The switch can be brought to rest in any desired position in which the level contact dis brushes the one-piece segment. The 22p must then be designed as a light I When the impulse series generated by the group selector IGW is ended the switch IGWZ) will also be set.

The succeeding impulse series sent out by the I subscriber extends over the group selector IGWb to any of the devices known per'se.

When the connection is released by, for example, the subscribed at station Tn replacing his receiver a circuit for the rotary-magnet is again set up over the releasing contact 20p as already described and the switch wipers of the group selector are restored tonormal. On the'release of relay C'conta'ctlsc is opened. Relay 1?. re-

leases and opens contacts 241' and 251' whereby also the connection set up over the switch MW is released. r r 7 When a busy signal isobtainedfrom all the lines outgoing from the switch MW ally the X relays are energised as already mentioned. Relay G releases at the same time opening contact 31g; The group selector IGW'then cannot test to the 5th contact in level 4 as described, but reaches position 11 in which the rotary off -normal tion 11 has left the segment.

The impulse series is then restricted in. the moment the level contact (27c reaches this contact wll is closed. Relay P is energized over battery, resistance Wi2, rotary oil-normal contact wll, windings I and II of relay P, contacts ers dg'w-dgw are located in the positions 1-10,

is also opened as the switch wiper dgw in posi- The started switch MW is brought to rest by the release of relay R. The subscriber at station Tn receives the busy signal which is transmitted over earth, winding I of the busy signal repeater, rotary off-normal contact 11011, windings II of relays A and B,

" earth." When the subscriber replaces his receiver It should be noted, further, that a circuitarran gement obviously can be provided which brings the switch MW to rest on the eleventh step when a busy signal is received from all the lines which can be reached by this switch. It should also be mentioned that the impulses sent out during the free hunting of the group selector IGW when a busy signal is received from all the lines outgoing from the switch MW are ineffective as the switch MW has not hunted and the contact 2'7t has not yet been closed.

An embodiment is shown in Fig. 3 which indicates that already at the vertical movement of the group selector impulses are generated for the setting of another group selector. Apart from this the arrangement corresponds to the arrangement according to Figs. 1 and 2. The group selector IGW is to have access to the internal group selectors, for example, group selector IIGWa over its levels 1, 2, and.3, while it generatesimpulses for the settingsof other group selectors, for example, IGWbwhen set to the levels 4-0. The switch MW in this embodiment is now located in the front of the first group selector. IGW instead. or" behind same.

It is now obvious that a further distribution ofjthe contact banks can be effected, for example, the levels 1, 2, and 3 being provided for internal connections whereas the levels'4, 5, 6, '7, 8, 9, and 0 can be used forthe setting up of connections over group selectors, for example, a group selector IGWb inanother exchange. If a subscriber requires a connection with a free line in the levels 1, 2, and 3 the same switching operations are initiated as were already described in conjunction with Fig. 2. When the subscriber sends out the first'inipulse a circuit for relayIR is set up over off-normal contact 1570 extending as follows: earth, off-normal contact 1570, contact 21p, relay R, contact 190 (closed on the seizure of the group selector) battery, earth. Contacts 241* and 25r are actuated when relay R is energized, this causing the switch wiper cmw of the switch MW to be earthed and the circuit for the rotary magnet Dmw to be set up. The switch MW hunts for a free outgoing line in the manner already described in conjunction with Fig, 2. If the connection extends internally the contact 21p is opened at the energization of the test relay P, this causing relay R to release. Relay R effects the release of the switch MW with the result that the line seized by this switch is released.

If the subscriber requires a connection which effects another exchange over the switch MW he,

this occurs thefollowing circuit forthe vertical magnet H; is set up accordingly: earth, contact 5a, contact 90, winding II of relay V, contact 17d, lower contact at the rotary oil-normal contact 16w, winding of vertical magnetH, battery, earth.. The vertical magnet H is energizedand lifts the switch wipers agw, bow, cgw, and Die one step. The off-normal contacts 1370, 147a, and 15k are thrown overt By the closing of contact 151e,.the switch MW starts as already described to hunt for a free line, forexamp'le-the line La4, Lbl. The contact 14k prepares the circuit for the rotary magnet. The contact 1370 disconnects the exchange signal AZ from the subscribers line. If relay A is re-energized after the first impulse the contacts. 2a-5a are thrown over. Contact 4a causes a short circuit of windings II and'I of relay V whereby this does not release during the impulse series due to its retardation. When relay A releases at the second impulse the contacts associated with this relay take up the positions shown in the drawings. The throwing over ofcontact 2a causes no interruption in the operations as contact 22p has not yet beenactu .ated but contact 100 has been maintained open during the impulse series. If the ver ical magnet H is energized at the second impulse the switch wipers of the group selector IGW are connected up infront of the second contact bank. =These switching operations are repeated until the group selector arrivesin front of the, contact bank 4. When this occursthe earthed contact D is connected to the level contact 4 whereby a circuit to the connected group selector IGWZJ is set up as .follows: earth, level contact Dlc,

contact segment i, line st, contacts 3a, 22p,,line,

La3, contact 2%, wiper amw of the switch MW, line Lad, relay A1 at the'group selector IGWb, battery, earth. Relay .Al is energize and efiects the setting of the group selector IGWb on to the first level. When the fourth impulse has arrived the contacts 2a-5 a arethrown over whereby also the impulse arriving to relay A1- is ended by opening contact 3a.

It will be mentioned in this connectionthat contact 3c is not absolutely necessary. The

impulse series could, for example, be transmitted over the level contact dlc if this contact or the contacts swept by the same are-so designed that sufficiently long make and break intervals are obtained during the'brushing oi the level contacts l0.

When'the group selector IGW is' raised a further step by the succeeding impulse the contact Dlc will be found on the level contactfi. In such a case a further impulse will be transmitted to a relay ,Al which'will be out ch as soon as relay A is caused to be energized, When the impulse series is ended, that is to say, when relay A has been maintained an extended period, relay V will also release. Asa result a circuit for the rotary magnet D will be set up over the contact 111). The rotary magnet D causes the rotation of the switch wipers agwDk of the group selector in the fifth contact bank. Contact 16w is opened and contactl'ld closed whereby relay B is energized. Relay V among others opens contact 11v causing the rotary magnet D to be dis connected from battery. The switch wipers of the group selector are advanced by the interaction between-relay V'and the rotary magnet D until'relay V is energized. This will occur as soon as the switch wiper cgw has reached the tenth I contact in level 5 when the following test circuit is set up: earth, battery, contact 319, tenth contact in the contact bank 5, switch wiper cow,-

winclings II and I of relay P, contact 2a, contact 70, earth. Relay P is energized and actuates its contacts. By means of contact 18p it prepares a locking circuit for itself. Contact 20p opens the energizing circuit for the rotary magnet D. Contact 19p prepares acircuit for the short-circuit of winding 11 of relay V. By the opening of contact 21p the energizing circuit for relay R will be opened. This relay, however, does not release as'the level contactDJc connects earthto relay R over the resistance Wil. Contacts 222: and 23p have now switched through their connection. v

The subscriber is now in a position to set the switching devices located behind the group selector IGWb by the sending out of further impulse series. These impulses do not influence the magnets D and H. Relay V is energized at the first impulse by the throwing over of contact 5a to normal over earth, contact 55;, contact 90, windings II and Iof relay V, rotary magnet I-I, battery, earth. The vertical magnet H is not energized in this circuit due to the special resistances connected with relay V. Relay V actuates its contacts and opens contact 101) in order to prevent the impulses sent out over contact 2a from charging the condenser K01. The wind- II of relay V is short-circuited by contact 1222 with the result. that this relay does not release during the impulse transmission as the short-I circuiting of winding II of relay V causes this relay to function as a slow-acting relay.

It should" also be noted that by applying battery to the tenth contact of the contact bank l -O of the switch wiper cgw over contact 31g it will be achieved that, the group selector is brought to rest on the tenth stop. This precau tion has been taken in order to restore the switch to normal with as few steps as possible when releasing. The switch could obviously be brought to rest on any other contact in the corresponding contact bank.

When the connection is to be released the subscriber Tnl replaces his receiver whereupon the relays A, B, and C release. Relay C closes contact 8c and causes the release of relay B by short-circuiting the winding II of this relay. Relay R is disconnected from battery by means of contact 190 and releases, thereby releasing the switch MW. The switches located behind the group selector IGWb are also released by the opening of the circuit for the windings of relays T, X, and C2 when these relays released. On the closing of contact 20p a circuit for the rotary magnet D is setup which extends over earth, contacts 20p, 14k, and .1121. The, rotary magnet sets the switch wipers of thefirst group selector IGW into position 11. At the same time it causes contact 'l'ld to be closed- Relay V is en- 1 1 relay R energized.

- tact 80.

upon the switch wipers of the group selector le'ave the contact banks and drop into their normal position by their own weight. The offnormal contacts 13k, 14k,and lslcare opened whereby the original position of the system is again restored.

Should all the lines outgoing from the switch MW be busy at the initiation of a connection over this switch relay G also will have released. This relay opens contact 31g. This causes the group selector IGW to hunt freely until it reaches position 11. In this position the test relay P will be energized over the resistance Wi and contact wll. The test relay P opens the circuit for relay R by means of contact 21p. RelayR releases as also the level contact Dlc is set'in position 11, that is to say has left the associated segment with the result that the earth applied to the level contact cannot maintain The'switch MW is released and the subscriber received the busy signal over contact" 11011. Whenhe' replaces his receiver relays A, B, and C are released. Relay C causes relay P to be short-circuited by means of con- Relay P also releases and causes the setting of the switch IGW to normal in the already described manner.

If, at the settingup of internal connections all lines outgoing from the first group selector in the corresponding level are busy relay P will only be energizedwhen the switch has reached the position 11. In such .a case the switch MW which has been set at the first number impulse will be released bythe opening of contact 21p. The subscriber then receives a busy signal whereupon he can release the initiated connection by replacing his receiver.

What is claimed is: t

1. In a telephone system, a first exchange, a second exchange, a trunk line extending from said first exchange to said second exchange, a switch at said first exchange for setting up local connections, and means controlled by the setting of the switch at said first exchange for setting the switch at said second'exchange over said trunk line, s'aid means including contact groups'in the switch at said first exchange, multiple contacts in said contact groups the number of which .cor-

I responds to the groups of connected lines in the switch at said second exchange, and means controlled by said multipled contacts forgenerating impulses for setting the switch in said second exchange. t

t 2. A system as setforth in claim 1, in which the-impulses are generated by means of contacts in the contact bank of the switch in said first exchange which are brushed by the switch wiper.

3. A system as set forth in claim 1, in which means are provided for transmitting impulses overthe wipers of the switch at said "first exchange located in the speaking leads.

4. system as set forth in claim 1, characterized by the provision of a locking device in said first exchange to prevent the switch in saidfirst exchange, which is operated to set switches in saidsecond exchange, from seizing a trunk to said second exchange when the trunks thereto are notavailable. f

'5. In a telephone system, a first exchange, a second exchange, a vertical and'rotary switch in the first" exchange, local trunk lines connected in one or more levels ofv said switch, means for tive if said switch selects a non-local level for transmitting impulses over the selected trunk line during the rotation of said switch over the selected level.- V I i 6. In a telephone'system, a switch having a primary movement and a secondary movement, a plurality of other switches, means responsive to the primary movement of said firstswitch for selecting one of said other switches, and means effective during the secondary movement of said first switch "for transmitting impulses to the selected other switch. i

'7. A system as claimed in claim 6, in which the number of impulses transmitted is determined by the extent of the primary movement of said first switch.

8. In a telephone system, a switch having a primary movement and a secondary movement, a pluralityof other switches, means responsive to the primary movement of said first switch for selecting one of said other switches, and means responsive to a continuation of said primary movement for transmitting impulses to the selected other switch. a a

9. A system as claimed in claim 8 in which the number of impulses transmitted to the selected other switch is governed by the extent of the primary movement of said first switch. 10. In an automatic telephone system, a first exchange, a calling subscribers line appearing therein, a second exchange, trunklines interconnecting the exchanges, a switch in the first ex change, a hunting switch individual thereto for selecting an idle one of said trunk lines, switches in the secondexchange accessible over said trunk lines, means controlled over saidsubscribens line for directively operating the switch in said first exchange a predetermined number of steps, means responsive to the directive operation of said switch for causing said hunting switch to selectan idle switch in the second exchange over one of said trunk lines, means for automatically controlling the switch'in the first exchange to take the same number of steps taken previously by the directive operation, and means for automaticallycontrolling the switch in the second exchange, the automatic control of the switch in the second exchange being governed by the stepping action of the switch in the first exchange under its automatic control.

11. In a telephone system, a switch having a primary and a secondary movement, a plurality of other switches, means responsive to the primary movement of said first switch for selecting one of said other switches, means depending upon theextent of the primarymovement of "said first switch for determining the extent of "the secondary movement of the switch, means controlled by the secondary movement of said first switch for transmitting impulses to the selected other switch to operate thesame ina primary movement, the extent of the primary movement of said second switch being governed "by the extent of the secondary movement of said first switch, and means for automatically controlling said secondswitch inits secondarym'ovement.

ALEXANDER BRUNO passes. 

